Electric induction heater or furnace.



A.\HELFENSTBIN. ELECTRIC NDUCTION HEATER 0R FURNACE.

APPLIGATXON rum) JUNEs.1g12.

1,093,328. Patented Apr. 14, 1914. TIEL www Nitncses; Inu ex'xtmf LOISHELFENSTEIN, 0F VIENNA, AUSTRIA-HUNGARY.

ELECTRIC INDUCTION HEATER OR FURNACE.

Specification of Letters Patent. i Patented Apr. 14, 1914.

Application led June 5. 1912. Serial No. 701,893.

T0 all 'whom 'it may concern Be it known that I, ALors Hmrsssrmx, acitizen of Switzerland, and :t resident of Vienna, Austria-Hungary, haveinvented new and useful Improvements in' Electric Induction Heaters orFurnaces, of which the following is a specification.

In the case of induction heaters. in which the transforming of thecurrent is effected substantially outside the heater and the metal bathformsthe short circuit connection of the secondary circuit, it is foundto be of very particular advantage to utilize the metal heater orfurnace casing as the conductor of the secondary current to the metalbath The self induction of the extended lnetal bath that is to be heatedis thereby substantially lessened, as the introduction and return of thecurrent can be e'ectcd as near as possible to the bath and along thesame. The metal conductive furnace-casing .surrounds the metal bath thatis to he heated almost concentrically and' acts on all sides so as toreduce the self induction. Moreover.l the large surface of theconductire furnace-casing effects a good natural cooling of this'iixedlength of secondary current conductor. Further theicausing of thefurnace casing totake part in the conducting ot' the current rendersthel construction of the furnace cheaper and simpler. The. furnacecasing .may he so constructed that it can cai-r)Y the whole secondarycurrent, or in addition to the furnace-casing further special currentconductors for instance as .shown in l"i -l surroundingr the `sidesthereof nm)Y lw arranged for supporting it. l-`inall it is not necessarythat the whole furnace-casing .should lic employed in conlutixi r the.current. hut the casing may consist ol' elena-.nts which conduct the.secondary current and of elements which are not caused to take part iuthe conducting.

.f\n example ot' such a furnace or heater is illustrated in the drawing,Figure l lic-ins! a longitudinal vertical section, Fig. 2 a plan. andFig. 3 a transverse section` and Fig. -l a transverse section of a formof the furnace in which only a portion of the casing is employed assecondary current conductor.

1 indicates an extended furnace tube in which the metal Q to be heatedby the current is contained. At the ends of the tube water cooled poles3 are arranged` which transmit the induced secondar)r current on the onehand from the secondary winding 6 and on the other hand through thefurnace-casing 4 to the metal bath 2.

5 is` the primary winding of the transformer.

As shown in Fig. 4 only a part of the furnace casing needs to be causedto act as a conducting length for the secondary current circuit.

The furnace may of course be constructed so that it will turn or tilt.for instance b v suspending it between the foi-lcs T of a revolvingmember S rotating in the socket t), Fig, 4, and the hath he. movedduring the heating. Moreover, the furnace chamber above the hath may heenlarged for the cmployment of fuel.

Having now particularly described and ascertained the nature 'of my saidinvention and in what maner the .same is to he performed. I declare thatwhat I claim is:

An electric induction furnace. comprising an elongated furnace casingsurrounding the metal bath, com-entrically for reducing theSelf-induction, a transformer, water cooled poles at. the ends of saidcasing for trans mitting the induced secondary current through thefurnace casing to the hath to he heated, substantially as described.

In testimony whereof I ailix my signature iu presence. of two witnesses.

AQOIS lllldfllNSVlClN. lV itncsses:

Al. .s'r Femm-1n, IcNaz Ktoin'LANcnc.

